class Calc0018
  def initialize
    args = STDIN.readlines.map { |l| l.chomp.split(/\s+/) }
    @s = args.shift.first
  end

  def calc
    @s.split(//).map.with_index { |c, i|
      ((((c.ord - ?A.ord) - (i + 1)) % 26) + ?A.ord).chr
    }.join
  end

  def run
    puts calc
  end
end

Calc0018.new.run if __FILE__ == $0